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Thoughts on Air Filters for EA82T Long

I was talking to Will (WJM) earlier about his and my air filter on our EA82Ts. Nothing deep but he was talking about a post in which someone mentioned turbulence may be affecting the way his car is performing.

I figured I bring up something that I thought was interesting (at least to me it was). Yesterday, since it was great weather outside, I decided I would clean all the K&N air filters on my cars. In cleaning the K&N air filters, it's recommended that you run water from the filter outlet towards the outside of the filter. If you just rinse water directly through the filter, you can lodge dirt/grime into the filter itself so rinsing outward prevents this.

As I went through the K&N filters, I had only one ricer/no-name brand air filter that I figured I'd clean. It was the filter I purchased for the RX turbo. It was needed since the previous filter looked like it said in water for months, rusty as hell. Anyways, the K&N air filters rinsed through fine. However, the ghetto-ricer filter actually filled up with water. I was like The filter element didn't look restrictive and you could see a fair amount or light through the air filter itself. This filter actually looked cleaner than all of my K&N air filters. If this air filter holds water in like that, it has to be more restrictive than the K&N air filters. Some others here may think it's actually doing a better job since it is in fact more restrictive. Performance wise though, I can see where it may cause problems.

I'm going to show you why I am talking about this particular filter. You see, this air filter was previously on my Impreza Outback Sport. I had installed a used Minnam air intake on the Outback Sport and needed an air filter quickly to install so I put this unit on. I had the Outback Sport dyno'd not to long after installing this air filter. What I noticed is that it fell flat on its face at high rpms but did good on the low end. http://xt6.net/forum...nnamvsstock.jpg

I have been wondering recently if this is what attributed to my recent dyno run with this air filter installed.

Ok, here's a picture of the ghetto air filter that's on my RX Turbo and a K&N air filter that I have installed now on my Outback Sport. The K&N air filter is on the left while the ghetto-no-name air filter is on the right. Looking at them doesn't seem to show any defects or what not. The Ghetto air filter 'looks' fine and seems like it should flow fine.

Here's a close up look at the K&N air filter that I really like and why I purchased it.Notice how the center of the air filter seems to allow air to flow through it as well as letting air come in from the sides. There's not just a 'cap' on the top of the air filter. It also curves inward toward the air flow sensor. This is the opening in which the air flow sensor (or maf adapter) would be attached too. This inward center design may aide in controlling turbulent airflow somewhat rather than just letting air come in the sides of the filter and flow uncontrollably through the maf (if the screen on the maf sensor housing doesn't help control turbulent airflow).

This is the ghetto Autozone air filter. Look at how it's constructed inside as if it was thrown together. Also noticed that the top part of the filter is 'capped' off. There is no airflow allowed through this part. So the K&N air filter has more surface area for air to flow through than this filter. *Note* Some K&N air filters are made just like this also (meaning with the center 'cap' portion).

Here is a top view of both of the air filters.The K&N air filter is on the left while the Autozone ricer filteris on the right. Again, notice how the extra air filtering on the top of the K&N allows for more air flow through the filter and how it's construction may aide in guiding in turbulent airflow. The Autozone filter only allows airflow through the side, nothing from the top.

I just felt I'd share some info with some folks that may be interested. This is something for any newbies (like me) to ponder over when considering purchasing an air filter for their ride. Remember, that Autozone air filter would not let water pass through it (or not enough of it) until I really cleaned it. And the water flow through it was still not comparable to any of my K&N air filters I cleaned.

I do have one K&N air filter that's on my Toyota Matrix (An AEM intake) that's designed exactly like that Autozone air filter. I'm not saying that the Autozone air filter is crappy by design because of the less surface area of filter for air to flow through. I'm just stating why I think the K&N air filter that's open from the top is superior. Also, I'm pointing out that those aftermarket air filters like the Autozone one may not flow well or even worse than stock. Be careful how you choose.

I have no proof of any of this. So those two air filters I have shown, I'll be taking up to the dyno and swapping them between runs to see if there is any difference in hp/torque and/or air/fuel ratio mixture. It would be interesting and maybe even funny if the top end is restored simply from an air filter swap. I doubt it though. I doubt everything...so I test. That's all for now!

heres somethin else to cook your noodle. placement of the filter and the source of the air. my intake is a homebrew with a 6" k&n cone. it looks decent, and im sure it performs better than stock. i cant really be sure, because that was one of the first things i did to the car when i got it, and it ran like ***** then. it was running on 3 cylinders and had 3 exhaust leaks... anyway, skip pointed out that the way i have the intake set up now, it might be sucking more air in, but its all hot air from the engine bay. i wanna redo it so it sucks FRESH air from a duct cut through the side of the fender, like on those new land rover LR3s. im just hoping that ill be able to find a spot to cut the whole way through.

skip pointed out that the way i have the intake set up now, it might be sucking more air in, but its all hot air from the engine bay. i wanna redo it so it sucks FRESH air from a duct cut through the side of the fender, like on those new land rover LR3s. im just hoping that ill be able to find a spot to cut the whole way through.

Skip makes a good point. I don't know what type of testing facilities you have but don't just take people's word for what they say if you have a way to test it for yourself. It can be via dyno, drag strip, G-Tech, stop watch, etc.

This is what I did on on of my XT6s and I posted the results at the XT6.net site. I tested the stock setup, stock setup with snorkus cut and ducting attached going out to foglight, and an open air K&N air filter attached in the engine bay with pre-made piping.

The cold air of the stock snorkus cut and routed through the foglight made a significant difference in my trap speed. It brought it up from the stock 78-79mph range to 81mph range at the dragstrip. However, despite the open-air K&N air filter I had sucking in hot engine bay air (especially when the cooling fan came on), my trap speed with this setup was in the high 82/low 83mph range. It seemed my right-off-the-throttle torque was affected some due to the hot air sucking in at idle but once it started moving, the hot engine bay air played less of a part in hp/torque reduction.

Good to test out though to see for yourself and let us know what you come up with.